Heat recovery ventilators [1] are reasonably common in Canada. Most (all?) EnergyStar homes [2] have one, and they includes most if not all the houses I've look

Heat recovery ventilators [1] are reasonably common in Canada. Most (all?) EnergyStar homes [2] have one, and they includes most if not all the houses I've looked at (or friends have bought) in the past decade or so. I lived in a house built around 1985 that had one, which was R-2000 [3], so they're at least that old. [1] https://en.m.wikipedia.org/wiki/Heat_recovery_ventilation https://en.m.wikipedia.org/wiki/Heat_recovery_ventilation [2] https://www.nrcan.gc.ca/energy/efficiency/housing/new-homes/5057 https://www.nrcan.gc.ca/energy/efficiency/housing/new-homes/... [3] https://www.nrcan.gc.ca/energy/efficiency/homes/20575 https://www.nrcan.gc.ca/energy/efficiency/homes/20575